Acoustic echo is echo that may originate from the use of hands-free communication equipment with external loudspeakers and microphones. For example, acoustic echo may occur in a communication session between two participants when audio signals played out from a loudspeaker at one end of the transmission path are picked-up (or captured) by a microphone located at that same end of the transmission path and sent back to the originating participant at the other end of the transmission path. The originating participant will then hear the echo of the participant's own voice as he or she is speaking.
Acoustic echo can also be intensified in a number of scenarios. For example, acoustic echo may be intensified if sensitive microphones are used, the microphone and/or loudspeaker volume is turned up to a high level, or the microphone and loudspeaker are positioned in close proximity to one another. Acoustic echo can also be further aggravated by various acoustic effects (e.g., reverberation effects, wave reflections, etc.) produced by the user's environment.
Acoustic echo cancellation is an audio processing technique essential to providing speech enhancement (or voice quality enhancement) in many audio communication applications, including, for example, VoIP networks and telephony systems. An acoustic echo canceller (AEC), which is designed to remove echo from a signal captured at a microphone, allows audio communication sessions to progress more smoothly and naturally by preventing the annoyances and disruptions often caused by acoustic echo.
However, an AEC solution that is poorly designed, not operating effectively, or inappropriate for the particular location will not provide such benefits and can even degrade audio quality significantly. As such, there remains a technical problem in existing AECs that may not eliminate acoustic echoes such that some amount of residual echo remains.